Safety latch for crane lift hook



July 17, 1962 J. M. ZlTNEY, JR 3,044,134

SAFETY LATCH FOR CRANE LIFT HOOK 2 Sheets-Sheet 1 Filed May 28, 1959 INVENTOR JOHN M. Z/TNEY Jr.

Attorney July 17, 1962 J, M. ZITNEY, JR

SAFETY LATCH FOR CRANE LIFT HOOK 2 Sheets-Sheet 2 Filed May 28, 1959 INVENTOR JOHN M. Z/ T/VEY Jr.

3,044,134 SAFETY LATCH FGR CRANE LIFT HOOK John M. Zitney, In, Jefferson, Pa., assignor to United tates Steel Corporation, a corporation of New Jersey Filed May 28, 1959, Ser. No. 816,599 3 Claims. (Cl. 24-438) A further object of the invention is to provide a safety 1 latch for a lift hook which is rugged in construction, positive in operation and inexpensive to manufacture.

It is another object of the invention to provide a safety latch of the character indicated which can be easily and quickly installed on existing lift hooks without the necessity of drilling a hole through or otherwise weakening the lift hook itself.

These and other objects will become more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is a side elevational view showing the latch of the invention in open position;

FIGURE 2 is a front elevational view of FIGURE 1; and

FIGURE 3 is an enlarged side elevational view similar to FIGURE 1 showing the latch of the invention being engaged by the lift plate of a bail preparatory to opening of the latch.

Referring more particularly to the drawings reference character W designates generally a lift hook suspended from the block X of an overhead crane (not shown) for handling a rigid lift bail Y having an upstanding apertured lift plate Z thereon. The lift hook W is conventional in structure and includes a shank and a curved body portion which terminates in a tip spaced from the shank. The tip and the shank define therebetween the throat or load-receiving opening of the hook. The bail Y is also conventional in structure and may include any rigid type such as the C-hooks used to handle bundles of coiled strip material, grapples used to lift bundles of sheet material, etc. The structures thus far described are conventional with the exception of the safety latch of the invention which is designated generally by reference numeral 2 and is shown installed on the hook W.

The safety latch of the invention includes a bracket 4 consisting of a support plate 6 rigidly attached to the shank of the hook by means of a U-bolt 8 and an integral flange 10 which fit around the shank of the book. The bracket 4 also includes a pair of spaced parallel arms 12 which extend normal to the support plate 6 in a horizontal plane above the tip and throat of the hook.

Each of the arms 12 is provided with a generally vertically extending slot 14 which is enlarged at its upper and lower ends and has a reduced width in the intermediate portion between its ends. A latch plate 16 having lugs 18 projecting from the top edges thereof is disposed between the arms 12 with the lugs fitted in the slots 14. The plate 16 depends toward the tip of the lift hook W. The lugs 18 are shaped and dimensioned to rotate within the enlarged ends of the slots 14 and to pass through the restricted intermediate portions thereof when the plate 16 is tilted from its normal depending position. The centers of the lugs 18 are offset from the central plane of the plate 16 which extends from the top to the bottom of the plate. The vertical dimension of the plate 16 is such 3,044,134 .fPatented July 17, 1962 ice d that the bottom edge of the plate lies above the tip of the lift hook when the lugs 18 are disposed in the upper ends of the slots 14, as best shown in FIGURE 1. When the lugs'18 are disposed in the bottom ends of the slots the bottom edge of the plate projects into the throat of the lift hook and rests against the inner surface of the tip, as best shown in FIGURE 3. A striker flange or plate 20 is attached to and projects substantially normal to the inner face .of the plate 16 for a purpose which will be explained hereinafter.

In operation prior to engaging the aperture lift plate Z of a bail Y the plate 16 is initially positioned with its lugs disposed in the upper ends of the slots 14. With the plate 16 in such upper position, the lift hook W is manipulated by the crane operator to pass the tip of the hook through the aperture of the lift plateZ. As this is done the lift plate Z engages the plate 16 of the latch and tilts it toward the shank of the hook which causes the lugs 18 to drop. through the restricted intermediate portions of the slots 14 and come to rest in the bottom ends of the slots after the tip of the lift hook passes through the aperture of the lift plate Z. Then the lift hook is raised to lift the bail and transport it to its destination. During transportation of the hail the lift plate Z is prevented from disengaging from the hook by the plate 16 and the bracket 4.

After the bail has been carried to its destination and it is desired to disengage the lift hook W from the lift plate Z the lift hook is lowered until the bail comes to rest on the mill floor, storage rack or other support. Then continued lowering of the hook causes the striker flange 20 to engage the upper surface of the lift plate and be raised thereby so that plate 16 is raised and lug 18 moves upwardly through the restricted intermediate portions of the slots 14 into the enlarged upper ends, of the slots. When the lugs 18 are in the upper ends of the slots the lift hook is moved laterally to withdraw the tip of the hook from the aperture of the lift plate Z. During such lateral movement the lift plate Z pivots the plate 16 outwardly, as shown by broken lines in FIGURE 3, to permit disengagement of the hook. After the hook has been thus disengaged the plate 16 swings back to normal depending position by gravity.

When its desired to not utilize the safety latch of the invention for any reason, the plate 16 may be moved out of the way of the throat of the lift hook by rotating it l about its horizontal axis to turn its bottom edge upwardly and rest it against the block of the crane.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. A safety latch for a lift hook which includes a shank and a curved body portion terminating in a tip spaced from said shank, said latch comprising a bracket secured to said hook at the juncture of said shank and said curved body portion and extending therefrom over said tip, and a latch plate pivoted in said bracket and normally depending toward said tip, the pivotal connection between the plate and bracket including generally vertical slots in the bracket enlarged at their ends and of reduced width in the intermediate portions thereof, and lugs on said plate and passing through said slots, each said lug having a transverse dimension greater than the width of the intermediate portion of each slot and another transverse dimension at an angle to said first mentioned transverse dimension and of a width less than that of the intermediate portion of each slot, whereby said lugs will pass through said intermediate portions only when said plate is tilted from its normal depending position.

2. A safety latch for a lift hook which includes a shank a .7 3 t and a curved body portion terminating in a tip spaced from said shank, said latch comprising a bracket secured to said shank and extending therefrom over said tip, a

' latch plate pivoted in said bracket and depending toward said tip, the. pivotal connection between the plate and bracket including generally vertical slots in the bracket enlarged at their ends and of reduced width in the inte'rmediate portions thereof, lugs on said plate and passing through said slots,"each. said lug having a transverse dimension greater than the Width of the intermediate portion or each'slot and another transverse dimension at an angle to said first mentioned transverse dimension and hf a width less than that of the intermediate portion of each slot, whereby said lugs will pass through said intermediate'portions when said plate is tilted from its normal depending position, a striker flange extending substantially normal to one face of said plate whereby said plate can be manipulated to pass said lugs through said intermediate portions.

" 3. A safety latch for a lift hook which includes a shank and acurved body portion terminating in a tip spaced from said shank, said latch comprising a bracket secured to said shank and extending therefrom over said o 4 v tip, a latch plate pivoted in said bracket and depending toward said tip, the pivotal connection between the plate and bracket including generally vertical slots in the bracket enlarged at their ends and of reduced width in the intermediate portions thereof, aud lugs on said plate and passing through said slots, each said'lug havingv a transverse dimension greater than the width of the intermediate portion of each slot and another transverse dimension at an angle to said first mentioned transverse dimension and of a width less than that of the intermediate portion of each slot, whereby said lugs will pass through said intermediate portions when said plate istilted from its normal depending position.

References Cited in the file of this patent UNITED STATES PATENTS Peters June 16, 1959 

